The weight of a semi trailer is oftentimes a factor in determining the cost of delivering a load for commercial purposes. For example, maximizing the load weight allows a truck company to ensure that the customer is assessed the full price for transporting the load. The weight of commercial trailers is also important from the perspective of public safety and highway maintenance. Overloading a commercial vehicle can create a hazard by reducing the truck's stability and braking ability. An overloaded trailer may also cause wear to the trailer itself as well as to the tractor towing the trailer. Therefore, it is important to maximize the load at or near the vehicle's maximum weight capacity within the trailer without exceeding the predetermined weight limitations.
Governments typically regulate vehicle weight by specifying a maximum legal load limit and fining vehicle operators for any overage. Governments also typically regulate the maximum weight supported by every axle assembly of a truck and/or trailer traveling over pavement. For example, one illustrative regulation requires that the maximum load on any single axle assembly of a trailer may not generally be greater than approximately 20,000 lbs while the maximum total load on a tandem axle assembly including two axle assemblies may not be greater than 34,000 lbs.
A trailer typically includes one or more axles, such as a tandem axle assembly, including two axle assemblies, mounted on a suspension slider so it can be moved back and forth relative to the storage container of the trailer. By moving the suspension slider back and forth along a length of the trailer, the cargo weight can be distributed between the axle assemblies on the trailer and the tractor to prevent any single axle assembly from exceeding the maximum weight limit. For example, when the trailer suspension slider is moved forward closer to the tractor, the weight is shifted from the tractor to the trailer such that the trailer axle load weight becomes heavier and the tractor axle weight becomes lighter. When the trailer suspension is moved backward away from the tractor, the weight is shifted from the trailer to the tractor such that he trailer axle load weight becomes lighter and the tractor axle weight becomes heavier. In this scenario, more cargo may be loaded onto the trailer without exceeding the weight limits on each axle assembly of the trailer. Typically, the operator must move the suspension back and forth to evenly distribute the weight in order to meet the compliance of the maximum axle load weight. Moving the suspension slider for the tandem axle assembly back and forth typically involves several steps and considerable time.
Vehicle air suspension systems are known for controlling the ride characteristics of the vehicle. The air suspension assembly is typically coupled between a frame of the trailer and an axle of the trailer and is designed for absorbing shock from the axle of the trailer. The suspension assembly includes an air spring assembly for damping movement of an associated axle of the trailer when the trailer is traveling over a surface. The air spring assembly may be pneumatically controlled by the driver to control the ride characteristics of the trailer when the trailer is being pulled along the road surface. Typically, the air suspension system of a tandem axle assembly is configured such that the weight of the load on the tandem axle assembly is equally distributed between the two axle assemblies (i.e., the front axle assembly and the rear axle assembly). Equal distribution of the weight of the load on the tandem axle assembly between the two axle assemblies may operate to improve breaking and/or minimize tire wear.